The human neutrophil participates in host defense against infection through processes of chemotaxis, phagocytosis and microbial killing. Since the initiating events for each of these functions are thought to occur at the plasma membrane, further definition of neutrophil plasma membrane biology is essential to understanding normal and aberrant phagocyte function. Using a nitrogen cavitation method, we have for the first time isolated functional neutrophil plasma membranes as sealed vesicles. With this model we propose studies on the characterization of plasma membrane structure, composition and vicinal relationships using a combinaton of electrophoretic and radiolabeling techniques. Although interactions of stimuli with the neutrophil plasma membrane on intact cells is known to result in a series of metabolic events, little is known of the subcellular localization of these metabolic processes. With the development of methods to isolate neutrophil memebrane vesicles it is now possible to dissect membrane ionic electrochemical and enzymatic events from mitochondrial, lysosomal, endoplasmic reticulum and nuclear contribution. Flow dialysis methods will be applied to these questions. These studies on neutrophil plasma membrane structure and function should provide information which will have important implications for future studies on the diverse functional disorders associated with neutrophils.